Transmission type target, transmission type target unit, xray tube, X-ray generating apparatus, and radiography system

Abstract

A radiation emitting target, a radiation generating device, and a radiography system are provided in which adhesion between a target layer and a diamond substrate is improved and stable radiation emitting properties are exhibited. A transmission type target includes a target layer, a carbon-containing region including sp2 bonds, and a diamond substrate that supports the target layer. The carbon-containing region is positioned between the target layer and the diamond substrate.

What is claimed is: 
     
       1. A transmission type target for an X-ray tube comprising:
 a diamond substrate including an inner region which contains sp3 bonds and an outer region which contains a higher amount of sp2 bonds than the inner region; and 
 a target layer located on the diamond substrate and configured to generate an X-ray in response to irradiation with electrons. 
 
     
     
       2. The transmission type target according to  claim 1 , wherein the outer region comprises a carbon compound comprising sp2 bonds in a cyclic, linear, or three dimensional network main chain, or an allotrope of diamond, the allotrope comprising sp2 bonds. 
     
     
       3. The transmission type target according to  claim 1 , wherein the outer region comprises at least one selected from amorphous carbon, glassy carbon, diamond-like carbon, graphene, graphite, carbon nanotubes, graphite nanofibers, and fullerene. 
     
     
       4. The transmission type target according to  claim 1 , wherein the outer region forms a part of the diamond substrate. 
     
     
       5. The transmission type target according to  claim 1 , wherein the outer region is a continuous layer positioned. 
     
     
       6. The transmission type target according to  claim 1 , wherein the outer region has a thickness 0.005 times to 0.1 times a thickness of the target layer. 
     
     
       7. The transmission type target according to  claim 1 , wherein the target layer contains at least one metal element selected from the group consisting of tantalum, tungsten, and molybdenum. 
     
     
       8. A transmission type target unit comprising:
 the transmission type target according to  claim 1 ; and 
 an anode member connected to a periphery of the diamond substrate and electrically connected to the target layer. 
 
     
     
       9. An X-ray tube comprising:
 the transmission type target unit according to  claim 8 ; 
 an electron emitting source comprising an electron emitting portion disposed to face the target layer; and 
 an envelope that houses the electron emitting portion and the target layer in an interior space of the envelope or on an inner surface of the envelope. 
 
     
     
       10. An X-ray generating apparatus comprising:
 the X-ray tube according to  claim 9 , and 
 a drive circuit electrically connected to the target layer and the electron emitting portion and configured to output a tube voltage to be applied between the target layer and the electron emitting portion. 
 
     
     
       11. A radiography system comprising:
 the radiation generating apparatus according to  claim 10 ; and 
 a radiation detector configured to detect radiation that has been released from the radiation generating apparatus and has passed through a specimen. 
 
     
     
       12. A transmission type target for an X-ray tube comprising:
 a target layer configured to generate an X-ray in response to irradiation with electrons; and 
 a diamond substrate including an interior region which contains sp3 bonds, a supporting surface configured to support the target layer and a stress relaxation region between the interior region and the supporting surface in a thickness direction of the target layer, the stress relaxation region containing a higher amount of sp2 bonds than the interior region. 
 
     
     
       13. The transmission type target according to  claim 12 , wherein the stress relaxation region comprises a carbon compound comprising sp2 bonds in a cyclic, linear, or three dimensional network main chain, or an allotrope of diamond, the allotrope comprising sp2 bonds. 
     
     
       14. The transmission type target according to  claim 12 , wherein the stress relaxation region comprises at least one selected from amorphous carbon, glassy carbon, diamond-like carbon, graphene, graphite, carbon nanotubes, graphite nanofibers, and fullerene. 
     
     
       15. The transmission type target according to  claim 12 , wherein the stress relaxation region forms a part of the diamond substrate. 
     
     
       16. The transmission type target according to  claim 12 , wherein the stress relaxation region is a continuous layer. 
     
     
       17. The transmission type target according to  claim 12 , wherein the stress relaxation region has a thickness 0.005 times to 0.1 times a thickness of the target layer. 
     
     
       18. The transmission type target according to  claim 12 , wherein the target layer contains at least one metal element selected from the group consisting of tantalum, tungsten, and molybdenum. 
     
     
       19. A transmission type target unit comprising:
 the transmission type target according to  claim 12 ; and 
 an anode member connected to a periphery of the diamond substrate and electrically connected to the target layer. 
 
     
     
       20. An X-ray tube comprising:
 the transmission type target unit according to  claim 19 ; 
 an electron emitting source comprising an electron emitting portion disposed to face the target layer; and 
 an envelope that houses the electron emitting portion and the target layer in an interior space of the envelope or on an inner surface of the envelope. 
 
     
     
       21. An X-ray generating apparatus comprising:
 the X-ray tube according to  claim 20 , and 
 a drive circuit electrically connected to the target layer and the electron emitting portion and configured to output a tube voltage to be applied between the target layer and the electron emitting portion. 
 
     
     
       22. A radiography system comprising:
 the radiation generating apparatus according to  claim 21 ; and 
 a radiation detector configured to detect radiation that has been released from the radiation generating apparatus and has passed through a specimen.